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Law enforcement agencies across the UK effectively campaigned to use a face scanning system acknowledged as biased against women, young people, and individuals from ethnic minority groups, after complaining that a more accurate version produced fewer potential suspects.

The Technology in Practice

British police utilize the police national database (PND) to carry out searches using historical face recognition. This process involves matching a “probe image” of a suspect against a database of over 19 million custody photos to identify potential matches.

Acknowledged Discrimination

The UK interior ministry conceded last week that the system was flawed. This acknowledgment followed a study by the government's National Physical Laboratory found it misidentified Black and Asian people and women at much greater frequency than Caucasian males. The Home Office said it “had acted on the findings”.

“This raises the issue of whether facial recognition only becomes effective if users tolerate discrimination in race and sex. Operational ease is a poor argument for disregarding basic freedoms.”

Known Issue

Internal documents show that this discriminatory flaw has been known about for over twelve months. Furthermore, police forces argued to overturn an initial decision that was designed to mitigate the problem.

Senior officers were notified of the algorithmic discrimination in September 2024. The government-ordered laboratory study found the system was more likely to produce false positives for photos of females, Black people, and those under 40 years old.

A Policy U-Turn

In reaction, the national police leadership body ordered that the confidence threshold required for possible hits be raised to a level where the bias was greatly diminished.

However, this directive was overturned the following month after forces complained that the adjusted system was producing fewer “useful lines of inquiry”. Internal records indicate the stricter setting reduced the proportion of searches resulting in possible identifications from 56% to a mere 14%.

Severe Disparities

Although the Home Office and NPCC declined to specify what threshold is now in operation, the latest independent review discovered the system could produce incorrect matches for Black women almost 100 times more frequently than for Caucasian women at specific configurations.

The Home Office commented on these results: “Our evaluation found that in a specific scenarios the software is has a greater tendency to wrongly flag some population segments in its search results.”

Balancing Utility and Fairness

Outlining the effect of the temporary raise to the system's accuracy setting, the police records state: “The change greatly lessens the impact of discrimination across legally safeguarded attributes of ethnicity, generation and sex but had a substantially detrimental effect on police efficiency”. The papers further note that police units complained that “a previously useful tool returned results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has opened a two-and-a-half-month public review on its plans to widen the use of biometric scanning systems. Policing minister Sarah Jones has described the technology as the “most significant advance since DNA matching”.

Expert and Oversight Concerns

The chair of a police oversight board, head of the advisory panel for the national policing equality strategy, commented: “There was very little discussion in race action plan meetings of the facial recognition rollout even with obvious cross-over with the strategy's goals.

“This disclosure show yet again that the anti-racism commitments policing has undertaken via the equality initiative are failing to be integrated into wider practice. Independent assessments have cautioned that innovative tools are being implemented in a landscape where racial disparities, inadequate oversight and poor data collection continue to exist.

“Any use of facial recognition must adhere to rigorous official guidelines, be independently scrutinised, and prove it diminishes rather than compounds ethnic bias.”

Official Statement

A government representative said: “We takes the conclusions of the report with utmost gravity and we have implemented changes. A new algorithm has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled early next year and will be subject to evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will support officers to put criminals and rapists behind bars. There is officer review in each stage of the process and no further action would be pursued without trained officers carefully reviewing the results.”